Electric phonograph pickup



p 1941- c. EfSEMPLE, JR., ETAL 4,454

ELECTRIC PHONOGRAPH PICKUP Original Filed July 8, 1937 CHARLES E-6EM PLEJR. FRAN K J, MALAT iwf'wv y Patented Sept. 2, 1941 ELECTRIC PHONO GRAPHPICKUP Charles E.- Semple, Jr., and Frank J. Malat, Youngstown, Ohio,assignors to The Astatio Corporation, a corporation of Ohio Originalapplication July 8, 1937, Serial No.

152,550, now Patent No. 2,182,138, dated Decem- Divided and thisapplication July 5, 1939, Serial No. 282,876 2 7 Claims. (Cl. 179-10041)This application is a division of original application Serial Number152,550, filed July 8, 1937, now Patent No. 2,182,138, issued Dec. 5,1939. The present invention relates to the art of sound reproduction andmore particularly to means for operatively supporting the translatingdevice for converting the mechanical impulses caused by the movingrecord into electrical impulses suitable for use in electricalphonographs. Such supporting means are commonly termed pick-up arms andare so constructed that the stylus or needle of the translating devicemay rest in the groove of the record and move across the face of therecord as the record rotates.

The arms for supporting the stylus or needle of the translatingrdeviceare usually mounted adjacent their outer ends for pivotal movement abouthorizontal and vertical axes whereby the stylus or needle is allowed tofollow the undulations on the record face and move from the outerperiphery of the record towards the center along the spiral groove asthe record rotates. The arms are'counterweighted to balance the weightof the portion overreaching the record and the Weight of the translatormounted at the end of the arm. It is common practice to house andsupport the translator in a separate housing or casing which isattachable to the end of the arm. The primary object of the invention isthe provision of an improved reconstruction for the housing andimmediate support of the translating device.

Another object of the invention is to provide such a support in whichthe vertical plane of the needle is caused to assume a good averagetangency with the curve of the groove of the record as the needle movesacross the record and in which the support may be readily rotated tofacilitate the insertion and removal of the needle.

A further object of the invention is the provision in an assembly of thecharacter described of an improved means to swivably support theimmediate translator housing and support on the end of thecounterbalanced arm whereby the translator housing and support is heldin selected rotated position and its rotation limited to prevent unduetwisting of conductor cords extending from the translator back throughthe arm.

A still further object of the invention is the provision of an improvedconstruction for the arm proper.

These and other objects and advantages of the invention will becomeapparent from a considerationof the drawing and the following detaileddescription wherein there is specifically disclosed a preferredembodiment of the invention.

In the drawing: v I

Figure 1 is a plan View of a pick-up arm constructed in accordance withthe invention;

Figure 2 is a side view, partly in section, of the arm of Figure 1;

Figure 3 is a bottom view of the assembled translator and housingtherefor of the arm of Figures 1 and 2;

Figure 4 is an end view ing and support; and

Figure 5 is a perspective view of a sleeve used in the construction ofthe preferred embodiment.

Referring to the drawing wherein the same reference numerals are used fto designate the same parts throughout the various views, the pick-uparm of the invention consists generally of a translator housing andsupport [0, a, tubular central member 20 and a weighted end member 30.In' accordance with usual practice, the arm is movable about bothhorizontal and vertical axesand for this purpose a base 40, adapted tobe fastened to a suitable surface of the cabinet structure with whichthe arm may be associated, is provided and an arm 48 is pivotallymounted on the base 40 for movement about a vertical axis. To the outerend of arm 48 a pick-up arm is pivotally mounted by means of thehorizontal pin 53, thus providing for movement of the pickup arm about ahorizontal axis.

The weighted end member 38 of the pick-up arm consists preferably of asquare block of metal having an integral rounded shank 3| to fit withinan end of the tubular member 20. C'ap screws 25 passing throughapertures in the tube 20 and threaded into bores provided in the shank3| provide a rigid connection between the tube 20 and the block 30. Theother end of the tubular member 20 rotatably supports the translatorhousing [0 which is provided with a shank I3 fitting within the end ofthe tubular member 20. Shank [3 extends from an angularly disposed sideportion I2 of the housing H] and extending axially outward of the shankl3 and the adjacent wall of the housing is a tubular member l4 heldwithin the bore of the shank and the wall by the set screw I5. A fixedpin I! and a second pin I8 spring pressed outwardly by the coil springI9 are positioned diametrically opposite on the shank I3 radiallyoutward of the tube M.

A bushing 2| of Bakelite or other suitable material is secured withinthe tube 20 by the screw 29 and, as shown more clearly in Figure 5, anend of the bushing, which when the parts are asof the translatorhoussembled is adjacent the pins |l--l8, is cut away at 22 for a portionof its periphery to provide a 7 and has its end swaged over at I6 tosecure the V bushing and head together.

With the head in operative position both pins.

are within the cut away portion 22 engaging both shoulders 23 and 23' tohold the headiin' position. If the head is now'rotated to change theneedle or for other purposes, the spring pressed pin [8 rides over theinclined shoulder 23' and frictionally engages the' end surface of thebushing. The rotation'of the head is; lim- 'lel with the axis ofrotation of said head and a shank fitting within the free end of saidmember, a translating device within said head, a

bushing secured within said tubular member,

said bushing, a pair of circumferentially spaced pins in said shankextending in a direction paraladapted to engage the adjacent end of saidbushited by the engagement of pin I! with shoulder.

23'. Thus any excessive twisting of .the. conductor 41 is prevented. Thefrictional engagement of the pin l8 with the end of the bushing holdsthe head in rotated position while the needle is being changed;

A plate I5 and screws 6 clamp the cartridge H to the side wall of thehead. The translating cartridge H is provided with a needle receivingsocket 1 and a set screw 8 to engagethe needle and hold it rigidly inthe socket. Thumb and finger engaging members 9 are provided to facilitate rotation of the head. 7

As shown in. Figures 1 and 3 the cartridge and the plane of the needlecarried thereby is disposed at an angle to the longitudinalaxis of thearm. This arrangement enables the vertical plane of the needle to assumea good average tangency with the curve of the groove of the record,resulting in better reproduction and decrease in wear of the record andneedle. It should also be observed that a vertical plane. passingthrough the longitudinal axis of the arm 2ll+30 passes substantiallythrough the rec- 0rd engaging end of the stylus carried by thetranslator cartridge II, which arrangement obviates the tendency of thecasing [0 to rotate about the longitudinal axis of the arm due to theweight of the casing and the arm supported by the stylus. In practicethe parts arefitted with such accuracy that the translator casing IDwill not vibrate independently of the arm as a whole. 7 7

It should now be apparent that we'have provided improved features in theconstruction of a pick-up arm which accomplishes the objects initiallyset. out. The stylus supporting means carried by the end of the arm isso arranged that the vertical plane ofthe stylus is caused to assume agood average 'tangency with the curve of the groove of the record withwhich the arm and translator is intended to be associated, whileenabling the means to be readily rotated to facilitate theginsertion andremoval of the stylus or needle. The structural features of the arm as awhole, including the use of the block 30, results in a well balanced,rugged and easily constructed device'which' in practice has been foundto produce excellent results in the reproduction of sound from therecords. The above specifically described embodiment of the inventionshould be considered as illustrative only as obviously many changesmaybe made therein'without departing from the spirit or scope .of' theinvention. v

What we claim is: r v j i 1.A pick-upv arm' comprising a swingablymounted tubular member, a hollow head having means to urge the sameoutwardly, one shoulder of said cut-away portion being inclined wherebythe spring pressed pin may override the same.

2. A pick-up arm comprising a swingably .mounted tubular member, arigidly mounted non-metallic bushing within said member adjacent thefree end thereof, a tube rotatably mounted within said bushing andextending beyond the free end of said tubular member, means to preventoutward longitudinal movement of said tube, a carrier for a translatingdevice rigidly secured to the outer extended end of said tube, and meanslimiting the relative rotation between said carrier and said bushing.

3. A pick-up arm comprising a swingably mounted tubular member, arigidly mounted bushing in said member adjacent the free end thereof, atube rotatably mountedwithin said bushing and extending beyond the freeend of said tubular member, means to prevent outward movement of saidtube, a carrier for a translating device rigidly secured to the outerend of said tube, the outer end of said bushing being provided with adepressed portion having an inelined shoulder, a rigidly mountedprojection and a spring pressed projection extending from said carrierand adapted to enter said depressed portion, the inclined shoulderenabling said spring pressed projection to ride out of said depressedportion upon rotation of said carrier.

7 4. A pick-up arm for an electric phonograph comprising in combinationan elongated block of heavy material having a boss extending from oneend thereof, means to pivotally support said block adjacent said bossfor movement about a horizontal axis, a tubular member having one of itsends fitting over said boss, a housing for a translating elementswivably mounted on the other end of said tubular member for rotativemovement about the longitudinal axis of said tubular member, saidhousing having an extended portion obliquely positioned with respect tothe longitudinal axis of said tubular member, the translating elementcomprising a casing inclosing a piezo-electric crystal and a needlesupport being received in said extended portion and being provided witha record engaging needle lying in a vertical plane passing through thecenter of said extended portion. 5. A pick-up army for an electricphonograph comprising in combination a generally horizonthe longitudinalaxis of said arm, said housing comprising spaced parallel side Wallsextending obliquely with'respect to said axis, a translating devicecomprising a casing. enclosing a piezoelectric crystal and a needlesupport adapted to be received between said walls, means to seplate andmeans to clamp said plate to one of the side walls of said housing withsaid casing thereinbetw'een.

'7. A device according to claim 5 further in- 5 eluding a manuallyengageable knob on the outer side of each of said Walls to facilitaterelative manipulation of said housing.

CHARLES E. SEMPLE, JR. FRANK J. MALAT.

